The qwen38 request loaded with "n_ctx : 2048" and failed on any real prompt. The
config says 32000 — but it was added to models.json after the engine started, so
the engine's registry didn't have it. The front DID know the alias and routed the
request, the backend resolved the alias to a local GGUF through its bare-path
fallback, and with no n_ctx in the load kwargs the code took llama.cpp's 2048
default. Nothing in the log explained why a 27B model suddenly had a 2k window.

So when no n_ctx arrives with the request: look the config up by the resolved path
(the manager's _config_for_model already resolves id/alias/basename), and only if
that finds nothing fall back to min(native context, 32768) with a warning naming
both numbers. On all three models on this box that turns 2048 into 32768.

The immediate cause still needs an engine reload to pick the new entries up; this
is about the failure being silent and the floor being useless.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0182DhR1eFNPQyGmDrpHbedY